High pressure gas and oil deposits underground can explode through an oil well, gushing oil and gas into the environment, causing explosions killing people, and inflicting tremendous damages to the environment and wild life. Such risks to human and environment though not limited to off-shore wells are particularly severe and difficult to manage at deep ocean off-shore sites. Case in point is the Deepwater Horizon drilling rig explosion that occurred Apr. 20, 2010 at the Macondo prospect oil field in the Gulf of Mexico. The explosion resulted in the sinking of the rig, 4.9 million barrels of crude oil spewed into the ocean, 50 billion cubic feet of methane gas spewed into the environ, and 2 million barrels of dispersants injected into the sea. Many estimated that the Deepwater Horizon disaster has caused damages in the order of a hundred billion US Dollars, and inestimable further damages yet to unfold.
A conventional blowout preventer (BOP) used in hydrocarbon wells is a costly and massive contraption. The one used at the Macondo Well of the Deepwater Horizon disaster was about 53′ high×16′×16′ wide and weighing 300 tons. It is installed atop a well head with an approximately 36″ flange connection to a well pipe about 20″ in diameter. A blowout preventer is a complex multiple-stage pipe-shearing and ramming device powered by batteries, controlled electrically via electrical wiring and electronic communications circuitry between the blowout preventer and the drilling rig, all of which may fail when encountering hostile conditions such as fire, explosion, blowout, and human error. In the case of the Deepwater Horizon disaster, the blowout preventer's electrical components failed at the very beginning. Attempts to mechanically activate the pipe-shearing and pipe-ramming devices using deep-sea robots also failed because the drill pipe remaining in the blowout preventer jammed these devices. In addition, the blowout preventer was listing 12 to 16 degrees risking a catastrophic toppling. Postmortem examination of the blowout preventer showed extensive corrosion. There was no access to the well head and the well below the blowout preventer, and no means to remove the damaged blowout preventer before the well was sealed through a five month long conventional “bottom kill” procedure, during which a relief well was drilled to access the bottom of the problem well to plug it. If the casing system of the well is compromised, stemming the blowout hydrocarbon flow at or above blowout preventer would result in high pressure hydrocarbon breaching grounds below the sea floor and escaping through the sea floor.
Conventional remedial methods were tried and failed during the many months following the Deepwater Horizon drilling rig explosion. During that time, the oil spilled and the dispersant released into the Gulf of Mexico traveled wide with the gulf current, causing disastrous environmental and commerce damages. The conventional methods tried and failed included the use of coffered domes and top hats which are massive up-side-down funnels with a riser pipe at the top that were lowered over the hydrocarbon spewing broken pipe sections in hope of capturing the spewing hydrocarbon. Unfortunately frozen hydrate formed to block the riser pipe.
Another method that was tried and failed was the insertion of a thinner good pipe into the damaged pipe section in an attempt to capture some of the oil and gas flow. Unfortunately the hydrocarbon pressure enlarged the broken gap at the pipe section near the top of the blowout preventer and spewed out there instead.
Another method that was tried and failed was the pumping golf balls, tire shreds, ropes, knots, and other junk and mud into the blowout preventer, hoping to plug the pipe in the blowout preventer to stem the massive hydrocarbon flow. Unfortunately the high pressure hydrocarbon flow spewed out the junk with it.
Another method that was tried and failed was a hat-like contraption, called a lower marine riser package (LMRP), with a wide open bottom and a pipe at the top. This was placed loosely fitting over the cut pipe opening at the top of blowout preventer, hoping to catch some of the spewing hydrocarbon. Unfortunately, more than 75% of the spewing hydrocarbon was reflected off the hat-top of the LMRP and ejected down into the surrounding ocean.